I don't ask a lot of people to read this blog with an open mind, because I know most won't. (Volkai, I know you're different with respect to all that.)
This, I want you to try to read with an open mind, because it's the result of me doing some thinking as I was doing some RL work tonight, out and about doing some walking.
What you are about to read, over and above, is complete conjecture. I don't have evidence to it, but if it were to be true, I do believe it would be quite explosive.
Let's begin from what I understand to be the process involved:
What a number of Japanese players (and possibly others, but what we learned was that this was a set of Japanese players who at least had it advertised) did was that they used the Porta-Furnace (the picture posted here shows it in present Saruta), and then somehow used the Cavernous Maw (they literally had to be right on top of the damn thing with the Furnace) to go to Saruta [S], where, immediately upon zoning in, they received a Black Abyssite, completely (or at least partially -- we aren't clear as to whether the parties had a Tier III Abyssite or not) jumping the VNM Tier system.
(FWIW, I propose any player who popped the VNM Wyrm using an illegally-acquired Black Abyssite in this manner be banned, because of the massive proposed abuse which could well be involved.)
Now, if this is the case, we have a problem:
First off, the process of Synergy should've been simply terminated upon zoning.
Second, all that the use of a Cavernous Maw should be is as if one had crossed a "zone-line" into the corresponding zone in the Shadowrealm. It's basically a simple "zoning" plus a small cutscene.
Third, and here's the important part:
What has happened here is a crossing of codes involving Synergy, the Porta-Furnace, zoning by use of the Cavernous Maws, and the gaining of Black Abyssite.
Now, the only legal way to gain a Black Abyssite is to have a Tier III Abyssite, and use it to pop a Tier III VNM, which your alliance must defeat.
Even THEN, it's a probability situation only.
With all this in mind, my conjecture:
Unlike the Salvage dupes, which could clearly be excused as "spaghetti code" (that Salvage is done by one party of 6, the drops are allocated per party, but it's an action through Salvage itself), this exploit appears to me to be an intentional exploit, unauthorized by Square-Enix.
My conjecture is that somebody put in some code that wasn't supposed to be there.
I believe this was an act of commission, rather than omission.
The number of intersecting game mechanics, and the wide variation of those game mechanics, appear to make it not simply a matter of spaghetti code.
The clincher to me is the acquisition, upon zoning, of a key item only legally obtained through killing a monster (in this case, a Tier III VNM you popped, and, again, only through a probability motif).
Either this was somebody within Square-Enix coding, or someone got in. But I do not believe this was authorized (the only way it could be would be if Square-Enix intentionally put this in to get players banned), and I think Square-Enix, as it investigates players to ban, needs to isolate this code, find out who put it in, and deal with them accordingly.
This is going to get very interesting, I do believe.